Apparatus for coalescing foam



May 6,1941. L. DLLLON Em 240,495

APPARATUS FOR COALESCING FOAM Filed Sept. l2, 1936 v K INVENITORSLyZezZZozz Edwardgaz Patented May 6, wel

APPARATUS FOB COMESCING FUAM Lyle millon and Edward G. Ragatz, LosAngeles,

Calif., aneignen: tollnion Oil Companyof Caliiornla, Galliornia LosAngeles, Galli., a corporation or This invention relates to foamcoalescence and particularly'to the coalescence of hot foamy oil to forma gas-free liquid.

. Oil, such as a heavy residual petroleum oil fraction or the like, whenheated as when it is intr'oduced into a vaporizer or fractionatingcolumn where vaporization and agitation takes place. often forms a gassyfoam which persists for long Periods of time without coalescence. Whenit is necessary totransport such ioamy oil rapidly and in. largequantities from one point to another through pipe lines while hot,diiliculties in the fornrof loss of suction on the pipe lines to thepumpand hammering in the pumping system often are manifested, withattendant loss of pumping eiilciency and damage to pumping equipment.

The object of this invention, therefore, is to eliminate the diicultiesassociated with pumping hot foamy oil or oil carrying entrained gas, byproviding apparatus for rapidly coalescing the foam and freeing the gas.

It has been discovered that oil foam or froth can be rapidly coalescedby subjecting it to th influence of an intense electric field.

The invention accordingly resides in apparatus for coalescing foamwhereby the foamy body is subjected to an intense electric ileld tobreak the foam and release the gas to form a relatively gasfree pumpableliquid body. The invention resides more specically in apparatus forsubjecting hot foamyoil to the influence of an intense ionizing electricheld whereby the foam bubbles are rapidly broken, the gas released andthe oil coalesced to forma gas-free liquid body which may be readily andeiciently pumped.

Other objects and novel features of the invention will be evidenthereinafter.

'In the accompanying drawing wherein preferred embodiments of theinvention 'are disclosed by way of illustration:

Fig. 1 diagrammatically illustrates a general arrangement of theapparatus of the invention as 'associated with fractional distillationof hydrocarbon oil.

Fig. 2 is a sectional elevation of one embodiment of the invention.

Figs. -3 and 4 are sectionalelevations of alternative embodiments of theinvention.

Fig. 5 is a plan section taken on line 5 5 of Fig. 2.

Fig. 6 is an enlarged cross section of one of the electrode jets of Fig.3.

The apparatus is as follows:

Fig. lpdiagrammatically illustrates a convenrod-shaped electrodes il aresupported by means- I. of the lead-in insulator bushing iii. Thesev`rodtional hydrocarbonoil fractional distillation system employingrecirculation of bottoms or partially strippedmaterial. The main unitsof this system are as follows:

H is a 'tubular heater adapted tc-heat the 'hydrocarbon oil feed priorto its introduction into the intermediate vaporizing zone of thefractionating column C. A is the foam ooalescing chamber. P is a pumpadapted to recirculate the coalesced oil from the coalescing chamber tothe heater. E is a high potential electrical supply for" the electrodesin the coalescing chamber com-V prising a high potential step uptransformer T and a synchronous rectifier R.

Fig. 2 is a. sectional elevation of the coalescing chamber A whichcomprises preferably a verti cal gas-tight cylindrical tank i0 having alarge foamy oil inlet pipe ii, gas outlet pipe i2 and a coalesced oiloutlet pipe i3 at the bottom. At an intermediate section of thecoalescing chamber cylinder a horizontal coalescing tray ifi is providedwhich partially divides the chamber into upper and lower sections whichcommunicate with one another only through the opening i5 Where the traydoes not extend entirely across the cylindrical section. In the uppersection ofthe coalescing chamber a plurality oi vertical shapedelectrodes which are constructed of pointed wires or rods approximately1x6" in diameter and approximately on 3 centers are suspended with theirlower pointed ends directed toward the upper surface of lthe coalescingtray A liquid level operated float 2li is provided to operate the valve2i to maintain the coalesced liquid-level within the coalescing chamberapproximately at the liquid level line as shown at 22. The liquid leveloperated oat 2li thus operates the valve 2| to open it when the liquidlevel 22 rises above the line 22 to allow coalesced oil to flow outthrough the line i3 and to close the lvalve 2i when the liquid levelfalls below the line 22.

In Fig. 3, which is an alternative arrangement of rthe coalescingchamber, the apparatus is the same as that illustrated in Fig, 2 exceptfor the electrode and-the foamy oil inlet system. Here a disc electrode25 is concentrically placed just upon the liquid level line 22 andpartially closes the cylinder section at -that point. This electrode 25is supported by the rod 26 through the lead-in insulator bushing i8. Thefoamy oil inlet system comprises pipe Il which leads to an internal cir-.the coalescingtray intense ionizing electric iield from the pointed, 75

cular distributing manifold 21 which carries from its lower surface aplurality of4 nozzles 2l adapted to direct the foamy oil downward intheform of relatively small streams or sprays which impingeupon the uppersurface of the disc electrode 25.

Fig'. 6 illustrates an enlarged sectional view of one -of thedistributing nozzles of Fig. 3; In each nozzlel a rod electrode-29 isprovided attached to `electrode 25. The foamy ,oilv inlet makes con. Anection with the inside o f the launder 3|.

The'operationisias follows; v

ends of theelectrodes il. The effect of this ionizing electric field isto cause a rapid calescence of the foamy oil and freeing of gas so thatthe materiali passing from the top of the coa- 'lescing tray I4 andfalling to the lower section ,of the coalescing chamber through thepassageway I5 is a substantially gas-free liquid. Thatl portion .of theoil passing through th'e passage- I the inside of th nozzle at 30 andextending coaxially through the orifices thereof to way which stillremains 'foamy issoon coalesced upon standing in the lower portion ofthe coalescing chamber.

the oil ,Aare .returned to the fractionating column through the gasreturn line I2.

' ,-The 'substantially vgas-free. oil is withdrawn from the lowersection of the coalescing chamber through the oil outlet I3 and forcedAby means of pump Pinto .the heater H where it commingles with the feedmaterial passing through the heater tubes.`

The liquid level iloat control 20, as described -.hereinbefore, operatesthe, liquid level control The hydrocarbonll feed to be distilled issuplplied to the heater H at the feed inlet 35V and after being heatedjto a vaporizin'g temperature is introduced into theintermediatevyaporizing section V of the fractionating column C through.

the line 36. The unvaporized oil from the vaporizing section of thefractionating column passes downwardly through the stripping section Sthereof in' countercurrent contact with stripping steam introduced atthe bottom at 31.- The comb ined vapors from the oil feed and thestripping section of the column pass upward through the fractonatingsection F of the column in countercurrent contact with reflux condensateto produce overhead fractionated vapors in the conventional' manner.

It is now common practice to withdraw unvaporized oil from the bottom orfrom an intermediate zone of the stripping section of the fracvalve 2|.to maintain the liquid level vwithin 'the coalescing chamber atapproximately the line Y22.

The electrodes l1 are individually adjusted in 4 height so that thespacing between the lower ends thereof and theupper surface of the ooalescing tray I4 which vconstitutesrthe electrode of opposite polaritywill be just suilicient to prevent disruptive electrical dischargestherebetween when the foamy oil is normally flowing thereacross.

Potentials which have been found satisfactory are from 50,000 to 75,000volts. A

This high potential may be supplied from a high potential generator orany other suitable supply such as for example the high potential supplysystem E which comprises a high potentionating column and to recirculatethis wthdrawn oil to the heater to act as a heat storage medium toconvey additional heat of vaporization for the feed material to thevaporizing section of f the fractionating column. Heretofore, thiswithdrawn material has been pumped directly from the draw-off pointbelow the vaporlzing section of the column to the heater. This practice,however, has in many cases been unsatisfactory for the reason that thematerial withdrawn from the lower portion oi the fractionating column,to be recirculated, contained-a large proportion of entrained gas andfoam, which resulted in a material reduction in the volumetricefiiciency of the circulation pumps and in serious hammering due to thepresence of the gaseous material in the pump cylinders. Since the rateof recirculation of this material is generally much in excess of thefeed rate, the withdrawn foamy oil hasno opportunity prior to itswithdrawal from the column to coalesce into .a gas-free liquid which.

could'be readily and eiiiciently handled by the pumps. Moreover, thefoamis found even upon standing to persist for long periods of time sothatmspecial means are necessary to effect its cqalescnce. Y. A

in the.' present invention, therefore, the withdrawnpbtottoms materialfrom the lower portion of the fractionating column is introduced througha large line 39 into a coalescing chamber A. Here, asvshownl in Fig. 2,the foamy oil 'entering,the coalescing chamber is distributed in a layerover I4 where it i's subjectedt the tial transformer T, the output ofwhich is rectiliedl by means of the mechanical rectifier R to producehigh potential pulsating unidirectional current which is conductedthrough the lines 4|) and 4| to the lead-in insulator connection to theelectrodes Il and to the coalescing chambershell IU respectively.

In Figs; 8 and Il alternative arrangements of the electrodes and foamyoil distributors within the coalescing chamber are illustrated. In Fig.3 the foamy oil enters the A coalescing chamber through the supply linein to the circular distributor manifold 21. The foamy oil is projectedfrom the manifold through the nozzles 28 in the forms of streams orsprays toward the upper surface of the disc electrode 25. As the foamyoil passes out of the nozzles over the rod electrodes 29 it is highlycharged or ionized by the intense ionizing electric ileld formed aroundthe lower point of the rod electrode 29. As the thus charged foamy oillmpinges upon the electrode 25 the bubbles are rapidly broken and gasfreed to form a coalesced, substantially .gas-free oil4 which may bereadily pumped from the bottoml section of the coalescing chamber asdescribed hereinbefore.

In Fig. 4 another alternative arrangement of the foamy oil distributorsystem is illustrated employing a circular launder 3| over which thefoamy oil spills and falls in finely divided streams from the downwardlydirected points of the electrodes 32 to theupper surface of the discelectrode 25.

While the apparatus of this invention for coalescing foamy oil has beenshown in Fig. 1 by way of illustration, as applied to a conventionalfractional distillation system employing recircu- 1 lation of bottomsmaterial, it is obviously applicable to any other system where thecoalescence The gases thus freed from of foam is advantageous. Moreover,the method and apparatus of the invention is not limited to thecoalescence of foamy hydrocarbon oil but is equally applicable to thecoalescence of animal and vegetable oil and any other similar materialin which persistent foams may form for any reason.

The foregoing is merely illustrative of the apparatus of the inventionand is not intended to be limiting. The invention includes any apparatuswhich accomplishes the same results within the scope of the claims.

We claim:

1. Apparatus for coalescing foamy liquid comprising a tank, a atelectrode in said tank, means to pass the foamy liquid onto saidelectrode to form a layer thereon, a second electrode in the upper partof the tank adjacent to the surface of said flat electrode, means tocharge said electrodes to a high electric potential diierence, asettling chamber in the lower portion of the tank, and means toseparately withdraw gas and coalesced liquid from said tank. l q

2. Apparatus for coalescing foamy liquid comprising a tank, a flatelectrode in an intermediate portion of said tank, a pointed electrodein the upper portion of said tank, means to pass the foamy liquid oversaid iiat electrode and under said pointed electrode, means to transferfoamy oil from said at electrode to the lower portion of said tank andmeans to separately withdraw the gas and coalesced liquid from saidtank.

LYLE DILLON. EDWARD G. RAGATZ.

